Your thyroid gland produces hormones that regulate metabolism, energy, and growth. During pregnancy, thyroid hormones are essential for your baby's brain development, particularly in the first...
Your thyroid gland produces hormones that regulate metabolism, energy, and growth. During pregnancy, thyroid hormones are essential for your baby's brain development, particularly in the first trimester before your baby's own thyroid starts functioning. Both an overactive thyroid (hyperthyroidism) and an underactive thyroid (hypothyroidism) can affect pregnancy if not properly managed.
About 2 to 3% of pregnant people have a thyroid condition, and with appropriate monitoring and treatment, most have healthy pregnancies and babies.
An underactive thyroid is the more common condition in pregnancy. Symptoms include extreme tiredness, weight gain, feeling cold, dry skin, constipation, and low mood. Many of these overlap with normal pregnancy symptoms, which is why blood tests are important.
If you are already on levothyroxine (thyroid replacement medication), your dose usually needs to be increased during pregnancy, often by 25 to 50%. Your GP or endocrinologist will monitor your thyroid levels (TSH and free T4) regularly, typically every four to six weeks, and adjust your dose as needed.
Untreated hypothyroidism in pregnancy is associated with an increased risk of pre-eclampsia, anaemia, preterm birth, low birth weight, and, rarely, developmental issues for the baby. With proper treatment, these risks are significantly reduced.
An overactive thyroid is less common but still important to manage. Symptoms include rapid heart rate, weight loss or difficulty gaining weight, anxiety, tremor, heat intolerance, and frequent bowel movements. The most common cause in pregnancy is Graves' disease.
Treatment depends on severity. Mild cases may be monitored without medication. More significant cases are treated with antithyroid drugs, usually propylthiouracil (PTU) in the first trimester and carbimazole from the second trimester onwards. Your specialist will monitor your levels closely.
The UK does not currently recommend universal thyroid screening in pregnancy. However, thyroid function tests should be offered if you have a known thyroid condition, a family history of thyroid disease, type 1 diabetes or other autoimmune conditions, symptoms suggesting thyroid dysfunction, a history of miscarriage or preterm birth, or are on certain medications like lithium or amiodarone.
If you are concerned about your thyroid, ask your midwife or GP for a blood test.
If you were on thyroid medication during pregnancy, your dose may need readjusting after birth. Thyroid levels should be checked at around six weeks postpartum. Some people develop postpartum thyroiditis, a temporary inflammation of the thyroid that can cause a period of overactivity followed by underactivity in the months after birth. This usually resolves on its own but may need monitoring.
Your thyroid gland produces hormones that regulate metabolism, energy, and growth. During pregnancy, thyroid hormones are essential for your baby's brain development, particularly in the first trimester before your baby's own thyroid starts functioning. Both an overactive thyroid (hyperthyroidism) and an underactive thyroid (hypothyroidism) can affect pregnancy if not properly managed.
The UK does not currently recommend universal thyroid screening in pregnancy. However, thyroid function tests should be offered if you have a known thyroid condition, a family history of thyroid disease, type 1 diabetes or other autoimmune conditions, symptoms suggesting thyroid dysfunction, a history of miscarriage or preterm birth, or are on certain medications like lithium or amiodarone.
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